A known form of spring assembly comprises a plurality of longitudinally extending bands of springs disposed side by side and connected together by helical wires which extend transversely of the bands and embrace portions of the bands. Several kinds of bands of springs have been proposed for incorporation in spring interiors. One kind of band, a so-called continuous band of springs, is disclosed in U.S. Pat. No. 4,358,097 assigned to the assignee of this application. Another kind of band is disclosed in British Patent No. 2,143,731. Both of the bands of springs disclosed in these two patents comprise a single length of spring wire shaped to form a plurality of individual coil springs arranged in a row, one end turn of each coil spring lying adjacent to a top face of the band, and the other end turn of each coil spring lying adjacent to a bottom face of the band. The coil springs of the band of springs disclosed in the above identified U.S. patent are all of the same rotational hand, while the coil springs of the above-identified British patent are of a rotational hand opposite to the rotational hand of the adjacent coils in the same row. The adjacent coils of the bands of springs disclosed in both patents are interconnected to adjacent coils by a pair of interconnecting segments of wire integral with the coil springs. One of the pair of interconnecting segments is located in the bottom face of the band, and the other of the pair of interconnecting segments is located in the top face of the band.
When bands of springs of the type described hereinabove are assembled to form a spring interior, they are conventionally disposed side by side and interconnected by helical lacing wires, some of which lie in the top face of the spring interior and others of which lie in the bottom face thereof, the top and bottom faces of the spring interior being the faces defined by the top and bottom faces of the bands incorporated in the spring interior. Each helical lacing wire extends across the bands of springs and embraces portions of wires of the bands that extend transversely of the bands.
The presence of helical lacing wires in such continuous band spring assemblies can give rise to production problems and limit applications of the product. For example, the application of the helical lacing wires to the assembly must be performed mechanically in order to be practical, and such mechanical assembly can give rise to production machinery jams and production work stoppages. Furthermore, helical lacing wires in such a spring assembly can create undesirable noise and be a weak point in the assembly if the helical lacing wires are overstressed, bent, and caused to fracture. Furthermore, this assembly technique either requires that the bands of springs be assembled side by side in order to prevent voids between adjacent rows of coil springs, or, if the rows are spaced, results in holes or voids into which padding may fall and ultimately impair the appearance and comfort of the resulting product.
A known alternative to using helical lacing wires to connect individual rows of continuous bands of coil springs together is to place each band between two plies of fabric and join the plies in order to form blocks, strips or tubes. The blocks or tubes are then joined together in order to create a coil spring assembly. Adjacent blocks may be joined together with glue, ultrasonic welds or other media without requiring the use of helical lacing wires. Applicants' U.S. Pat. No. 5,127,635, which is fully incorporated herein, discloses such a coil spring assembly. Additionally, applicants' U.S. Pat. No. 5,669,093, which is fully incorporated herein, discloses a coil spring assembly in which the blocks, each containing a continuous band of coil springs, are integrally joined by joining the two plies of fabric defining the blocks in alternative planes. The method of constructing such a coil spring assembly is disclosed in applicants' U.S. Pat. No. 5,761,784, which is fully incorporated herein.
The coil spring product disclosed in U.S. Pat. No. 5,127,635 comprises a plurality of individual pockets formed within each strip or block by joining the opposed plies of fabric in transversely extending lines of attachment. However, each pocket within a block contains two adjacent coil springs which upon being compressed when subject to a load may contact one another, creating clicking sounds, or what is generally considered in the industry as "noise." Oftentimes, it is desirable to posturize a mattress or other bedding or seating product by making one section of the bedding or seating product firmer than another section. Numerous patents have disclosed multiple different ways of posturizing a bedding or seating product. In a pocketed bedding or seating product in which continuous bands of coil springs are located within fabric blocks or strips, one known method of posturizing such a bedding or seating pocketed product is to make the continuous bands of coil springs of different gauge wires. Select blocks contain bands of coil springs of a differing gauge wire than the bands contained in other blocks in order to posturize the bedding or seating product. Because the assembly of such a bedding or seating product requires bands of wire of at two different gages, the assembly of such a product is time-consuming and labor-intensive. Additionally, the resulting product is expensive.
Therefore, it has been one objective of this invention to provide an improved continuous band spring assembly which eliminates the presence of the helical lacing wires and/or any other wire product for interconnecting the adjacent bands of coil springs.
Another objective of this invention has been to provide an improved continuous band spring product which is quieter than prior art continuous band products because of the absence of helical lacing wires and the absence of any potential for coil springs of one band to rub against coil springs of adjacent bands or coil springs of the same band and thereby give rise to noise.
Still another objective of the present invention has been to provide a pocketed coil spring product which may be easily posturized without using continuous bands of coil springs of differing gauge wire.